When comparing DejaVu Sans Mono vs Terminus, the Slant community recommends DejaVu Sans Mono for most people. In the question“What are the best programming fonts?”DejaVu Sans Mono is ranked 1st while Terminus is ranked 18th. The most important reason people chose DejaVu Sans Mono is:

It's easy to distinguish between characters such as I, 1, l, O, and 0 in DejaVu Sans Mono.

Pros

Pro

Very clear distinction between similar characters

It's easy to distinguish between characters such as I, 1, l, O, and 0 in DejaVu Sans Mono.

Pro

Bold font is the same width as the regular weight font

The Sans Mono version is graphically close to Andale Mono (Microsoft core web font), slightly bolder, with the added bonus of the bold font being the same width as the regular one (unlike Andale Mono). It is a nice property with some syntax highlighting text editors.

Pro

Excellent unicode support

DejaVu Sans Mono has one of the most complete Unicode fonts available. This means you have access to a wide range of special symbols including mathematical symbols like arrows, operators, and special alphabets. This is useful for certain languages that require special characters like Agda.

Some languages allow using these characters optionally. There are editor modes that display characters like this without changing the underlying file, much like syntax highlighting. The Emacs modes for OCaml and Haskell are prime examples.

Pro

Clean, readable design

Reading the text is pleasant and effortless. Letter forms combine nicely into words.

Pro

Nice uniform spacing

The font is well spaced and doesn't break up words.

Pro

It's subtle, yet stilish and extremely readable, very easy on eyes and very effective for long development sessions

Pro

Available with every linux distribution and works fine in vim, emacs and atom

It's also included in modern versions of Windows.

Pro

Closely related to MobaFont

For MobaXterm users, this font closely mirrors the embedded MobaFont so they can use a monospace font across other applications.

Pro

Looks great even without anti-aliasing

Many fonts look terrible without anti-aliasing. Not Terminus, it looks clear and crisp.

Pro

Beautiful crunch pixels

Pro

Terminus is not going fat

Many fonts are fatty when they are used relatively large in size but Terminus does not have this issue. And now it works with IDEA.

Cons

Con

The "-" symbol is short

For example, when using the '-' symbol for borders, it's super short in this font.

Con

Tilde character lacks curvature

The tilde character in this font ('~') does not have enough curvature to be read easily at small sizes. This can be a concern for Unix(-like) shell users and script writers, as the tilde is used relatively often compared to other symbols.

Con

Crowded bold styles

At size 12, in bold text, some letters bump up against each other too closely, greatly reducing legibility.

Con

Dotted zero

Dotted zero is less readable than slashed zero

Con

Not suitable for Vietnamese

This font is really ugly when used with Vietnamese characters.

Con

Missing some Vietnamese characters

ấ, ề, ự, etc. are missing in DejaVu Sans Mono.

Con

No ligatures

Missing programming ligatures.

Con

Some characters are similar

Small 'L', capital 'i' and 1 are too similar.

Con

Italics are not very appealing

Italicized Terminus TTF doesn't appear as aesthetically pleasing as it was intended.